Concept art for what is said to be from the development of Half Life 2: Episode 3 has appeared on fan site Valve Time.
The images were submitted by an anonymous user and purportedly date back to 2008, so are unlikely to be an accurate depiction of the game as it is now, if it is in development at all at this point. Since there has been over five years since the release of the last chapter in the Half Life story, Episode 2, many have come to consider the sequel to be vapourware. Whether any of these screenshots do end up in the next Half Life game or not, they do however give an interesting insight into the direction the dev. team were considering going in, back in 2008.
For those who would prefer our description over viewing the images themselves, there's Alyx in various forms of attire, mostly cold weather gear and some panoramas, several of which feature a downed helicopter. A couple have silhouettes of one or two figures, looking out over large empty expanses. Two more feature combine looking technology and floating platforms. These are presumed to be referencing the parallel world of Xen.
There's also several versions of something that looks more like a tattoo design than something from a game. It has long, flowing cloth like appendages, with some sort of exploding energy at its centre. Some commenters have suggested it could be an artistic interpretation of a fully grown Combine Advisor.
The interesting focus on Alyx and silhouettes that can be presumed to be her - due to the character clearly wearing an eskimo style coat similar to the one worn by Alyx in other concept sketches - suggests a focus on her character instead of the usual protagonist Gordan Freeman.
For the full gallery of images, check out the Valve Time Facebook.